When tested against cases with a known culprit, the mathematicians could correctly list the gang rivalry involved (out of the three most likely rivalries) about 80 percent of the time. Of these options, they ranked the responsible gang first about 50 percent of the time.

To develop their technique, the mathematicians studied a combination of solved and unsolved gang crimes throughout East L.A. over ten years.

Imagine that! Mathematicians as crime-fighters!

Bertozzi is optimistic about the future of mathematicians as crime fighters. “We can do even better,” she says. “This is the first paper that takes this new approach. We can only improve on that 80 percent by developing more sophisticated methods.”